Apparatus for obtaining fluid samples from subterranean formations



Apnl 3, 1956 R. J. MONAGHAN 2,740,477

APPARATUS FOR OBTAINING FLUID SAMPLES FROM SU'BTERRANEAN FORMATIONSFiled Oct. 29, 1951 2 Sheets-Sheet l A32 1 .34 I 5 i Q39 4+ '38 i7 4$2.9 T 37 A 30 l if yak 1 46 46' y i 7 /9 T /E a L l 9 6 B. 7 INVENTORiii a ,3 A E/CHAEDJMONAGHAN 2, BY z); a 4 ATTORNEYS April 3, 1956 R. J.MONAGHAN 2,740,477

APPARATUS FOR OBTAINING FLUID SAMPLES FROM SUBTERRANEAN FORMATIONS FiledOct. 29, 1951 2 Sheets-Sheet 2 ATTORNEYS United States Patent 9APPARATUS FfiR OBTAINING FLUID SAMPLES FROM SUBTERRANEAN .FORMATIONSRichard 3. Monaghan, Baton Rouge, La.

Application October 29, 1951, Serial No. 253,644

11 Claims. (Cl. 166-63) This invention relates to means for obtaining,during oil well drilling operations, samples or specimens of formationfluid as it exists in the earths formation immediately below the bottomof the oil well being drilled.

It is a prime object of the present invention to provide forconveniently and effectively obtaining such samples or specimens offormation fluid in its natural condition uncontaminated by drillingfluid which is commonly employed in well drilling operations.

it is an object of the invention to provide for excluding drilling fluidfrom an area of the bottom end wall of the oil well and forming anopening through said area and a cavity in the formation therebelow, sothat there will be no opportunity for the drilling fluid to enterthrough the top of the cavity during the formation thereof.

It is a further object of the invention to provide for removingformation fluid from the cavity and trapping it in its natural physicalcondition uncontaminated by drilliug fluid.

Another object of the invention is to provide for sealing the top of thecavity as an added precaution against ingress of drilling fluid and alsoto prevent escape of formation fluid therethrough, thus preventing thewell from becoming active.

It is another object of the invention to provide a tool or instrumentfor accomplishing the foregoing stated objects in such a form that itmay be lowered through a drill string during drilling operations.

It is a further object of the invention to provide for effectuallyinserting the collecting nozzle of the device into the cavity and forwithdrawing it therefrom.

It is a further object to provide for forming the opening through thebottom end wall .of the well and the cavity in the underlying formationby the effect of an explosion applied directly against the bottom endwall of the well. Specifically it is proposed to use a so-called shapedcharge for this purpose.

Additional objects and advantages of the apparatus of this inventionwill become apparent from the following specification and claims takenin connection with the accompanying drawings, in which- Figure 1 is aview, partly in elevation and partly in vertical section, of oneembodiment of the device or tool of the present invention and asdesigned for carrying out the invention shown in its initial positionwithin the drill string.

Figure 1 is a view in vertical section of the top part of the deviceshowing the connection thereof with a drill string.

Figure 2 is an enlarged view in vertical section of the lower part ofthe device in engagement with the bottom end wall of an oil well inposition for excluding drilling fluid from an area thereof.

Figure 3 is a detail fragmentary vertical sectional view of the lowerpart of the device with the collecting nozzle in position to receiveformation fluid and lead the same into the trap chamber.

2,740,477 Patented Apr. 3, 1956 Figure 4 is a vertical fragmentarysectional view of a detail.

Figure 5 is a detail vertical fragmentary view of the device showingparts in position immediately prior to firing the explosive charge.

Figure 6 is a cross sectional view taken on the line 6-6 of Figure 5.

Figure 7 is a detail vertical sectional view taken through the top ofthe lower or barrel member of the device.

Figure 8 is a cross sectional view on the line 8-8 of Figure 1.

Figure 9 is an enlarged detail fragmentary sectional view of one half ofFigure 7 and at right angles thereto.

Figure 10 is a vertical sectional view taken through the breech blockmembers and showing the passage therebetween.

The tool or instrument of the present invention is designed for loweringan explosive charge through a drill string and bit into cooperativerelation with the bottom end wall of the well and to provide for firingthe explosive directly against said wall for the purpose of burning orblasting an opening in said wall and a cavity in the underlyingformation. It is also designed for sealing off a selected area of thesaid wall through which the opening is to be formed or in other words,for excluding drilling fluid from such area during the formation of theopening and the cavity prior to the firing of the charge.

In Figure l of the drawings, a vertical section of an oil well bore Chas ben shown in which is a core drill bit F secured by a screw threadedconnection to the bottom end of a drill collar E. The drill bit has beenshown as being in a retracted position a few feet above the bottom endwall of the well. The device or tool of the present invention has beenshown in this figure in the position in which it is placed prior toexploding the charge employed for forming an opening through the bottomwall of the well as shown in Figure 2 of the drawings.

The device for carrying out the present invention is either droppedthrough a drill string, which is of course full of drilling fluid, or itis lowered through the drill string in much the same manner as wire linecoring equipment. The device floats downwardly through the drillingfluid in the drill string and finally comes to rest in the positionshown in'Figure 1 wherein the descent of the tool has been stopped by anexternal annular shoulder 40 thereon engaging an internal annularshoulder 41 within the drill collar.

For convenience in lowering the device or tool, I propose to use anordinary or preferred form of 'wire line overshot 26 as shown in Figure1 of the drawings, suitably connected to the top of the present tool, aswill be explained hereinafter.

One embodiment of the device or tool of the present invention has beenshown in the accompanying drawings and includes a lower member A whichis here shown as being an open ended tube or cylindrical barrel, and anupper member 'B here shown as substantially cylindrical in shape, andtelescoped within the member A, and provided with a packing ring 6 toprevent leakage of drilling fluid between the members A and 'B. Asshown, the member B is provided with a longitudinally disposed chamber 1closed at its bottom end as best shown in Figure 2. A longitudinallydisposed passage '2 extends from the lower closed end of the chamber 1downwardly through the lower end of the member .3 which passage fluidwhich the present tool is intended to collect or obtain from below thebottom end wall of an oil well. In order that a larger quantity offormation fluid may be accommodated in the present tool than can be heldin the chamber 1, the member B may be made in two sections, a lowersection B and an upper section B" suitably connected to the open top ofthe member B, as by screw threads, shown in Figure 1. This section B"may be provided with a chamber 1', shown in Figure 1, open at its upperend so as to communicate with and form a continuation of the chamber 1.However, it will of course be understood that it is not necessary tomake the member B in two sections.

As best shown in Figure l of the drawings, the upper portion of themember B is reduced in diameter as at 3', thereby forming an upwardlyfacing annular shoulder 5 at the base of the reduced portion, whichshoulder is designed to normally engage upwardly against an internalannular shoulder on the member A preferably formed by the bottom end ofa bushing s screwed into the open top of the member A. The bore of thebushing 6' is provided with a plurality of open ended groves to slidablyreceive longitudinal ribs 7 on the reduced part 3 of the member B so asto center and guide the member B within the member A for a purpose aswill be hereinafter explained. A helical spring 8 embraces the reducedpart 3' of the member B. Its lower end bears downward against the top ofthe member A formed by the bushing 6 and its upper end bears upwardlyagainst an annular shoulder on the reduced part 3 which shoulder in thepresent em- Y bodiment of the invention, is the bottom of the uppersection B. Where the member B is not made in two or more sections asuitable shoulder or bearing may be provided upon the reduced part 3 forthe upper end of the spring 8 to bear against. This spring normallyholds the annular shoulder 5 of the part B against theannular shoulderprovided by the lower end of the bushing 6 and thereby prevents endwiseseparation of the parts A and B.

At the bottom of the open end of the barrel or member A there is atubular section 9 open at its lower end and provided at its upper endwith a reduced externally screwthreaded stem It engaging the internallyscrew-threaded portion of the lower end of the member A. The lower endof the member 9 is provided with a packing ring 10', preferably ofcompressible material, seated in a recess formed in the outer facethereof. The ring 10 is arranged with the lower edge thereof flush withthe lower edge of the member 9 and the outer face thereof flush with theouter face of said member. This section 9 constitutes a chamber forholding an explosive charge 11, provided in one end with a preferablyconical recess 12 and positioned in said chamber with the open end ofsaid recess presented downwardly. For holding and centering the charge,within the section or hell 9, there is an annular gland or nut 13 whichmay be entered through theopen lower end of the bell 9, and engaged withan internally screwthreaded part of the bell. The inner wall of thegland 13 is inclined upwardly and. outwardly and engages the lower edgeof the charge to force the same into engagement with the upper concaveinner wall 14 of the bell 9 to center said charge within the bell.

At suitable distance above the top of the bell section 9, there is aninternal nut 15 engaging an internally screwthreaded part of the memberA and provided with a centrally disposed opening or passage 16 which ispreferably flared at its upper end as at 17. This opening 16 constitutesa seat for a detonator or percussion cap 18 employed for setting off thecharge 11. Frictionally held between the top of the bell section 9 andthe nut 15 are a pair of breech block members 19 mounted to slidediametrically within the member A. As best shown inFigures 6 and 9,these breech blocks are provided with grooves 20 which, when the breechblocks are brought together will match and form a zigzag opening orpassage best shown in Figure 9 through which the flash or fire from thedetonator or percussion cap 18 may pass to the charge 11. The top of thebell section 9 is provided with an opening 21 through which the flash 0rfire may pass from the passage 29 to the explosive charge.

For firing the detonator or percussion cap, there is provided a firingpin 22 carried by and projecting downwardly from the member B in thelongitudinal center line of the member A so as to engage thepercussioncap or detonator as will be best understood by reference toFigure 5 of the drawings. Upon downward movement of the firing pin 22,after it has engaged and detonated a percussion cap, it will pass ondownwardly through the opening 29 between the breech blocks forcing themapart so that the firing pin may continue on downwardly through theopening 21 and further downwardly through the interior of the bellformerly occupied by the shaped charge prior to the explosion thereof.Closing the open bottom end of the out or gland 13 is a hood member 23suitably secured thereto for the purpose of preventing upward passage ofdrilling fluid into the interior of the bell 9 and against the shapedcharge 11. This member 23 is of suitable material, strong enough toresist the pressure of drilling fluid but capable of being broken ordestroyed by the effect of the explosion of the explosive charge, andtherefore the firing pin 22 may pass on downwardly through and beyondthe open lower end of the member A when the hood 23 has been destroyedor ruptured, The firing pin is provided with a longitudinal bore orpassage 24, the upper end of which communicates with the passage 2,inthe bottom end of the member B. The lower end of the firing pin ispreferably pointed as shown, to ensure a proper detonation of thepercussion cap, and a plurality of passages 25 areprovided through thefiring pin so as to atford communication between the exterior of the pinand the passage or bore 24, whereby formation fiuid as hereinafterexplained, may pass into the passage 24 and upwardly therethrough intothe chamber 1' within the member B. p

In lowering the device or tool through a drill string, the procedure ismuch the same as in the well known wire line coring method. A wire lineovershot 26 is secured to the upper end of the present device as by ascrew threaded connection 27. Within a socket or chamber 28 in the part26 is mounted an upright dog 29 pivoted at its lower end as at 30 sothat it may swing diametrically of the part 26 through a slot 31disposed vertically through the part 26 and through which slot the dogmay project beyond the part 26 as shown in Figure l. A spring pressedplunger 32 engages the back edge of the dog so as to force it outwardlythrough the slot 31 whereby the shoulder 33 on its top edge may engagebeneath a downwardly facing shoulder 34 within the drill collar. A bolt35 is slidably mounted through the upper end of the part 26 and isprovided at its top with a head 35 for engagement by the grapple of awire line. At its lower end the bolt is provided with a bifurcation orfork 36 straddling the inner or back upright edge of the dog. A lateralhook or foot 37 is provided upon the lower end of each arm of thebifurcation or fork, and a horizontal pin 38 extends across the two feetor hooks 37 and works in a slot 39 provided in the dog and inclined tothe vertical, so that by lifting the bolt, its fork will lift the pin 38through the slot and thereby swing the dog inwardly and withdraw theshoulder 33 from beneath the shoulder 34. The engagement of the dog withthe shoulder 34 prevents upward movement of the device or tool of thepresent invention independently of the drill string. Also, by loweringthe drill string, this same engagement will cause the present device ortool to move downwardly with the string.

. In the practice of the present invention by use of the present tool ordevice, the drill string E and the drill bit F being in the well C, asshown in Figure 1, with the drill bit at the bottom thereof and the welland the drill string full of drilling fluid, the drill string is liftedslightly, until the drill bit has been retracted a suitable distanceabove the bottom end wall of the well as shown in Figure 1 of thedrawings.

The device of the present invention is then dropped or lowered throughthe drill string and floats downwardly through the drilling fluid until.an external annular shoulder 40 on the barrel A engages an internalshoulder 41 within the bore of the drill bit, and the dog 29 snapsbeneath the shoulder 34- within the interior of the drill collar. Thebarrel A will then project a suitable distance below the drill bit withits lower end short of the bottom end wall of the well, as best shown inFigure l. The reason for retracting the drill bit is to provide roomenough below the drill bit and above the bottom end wall of the well toprevent contact of the barrel A with the bottom end wall of the wellwhen lowering the device into position for use thus preventing prematurefiring of the explosive charge. After the device has reached theposition as shown in Figure 1 of the drawings, the drill string islowered to bring the lower end of the barrel A into con-tact with thebottom end Wall of the Well, with sufficient force to embed the loweredge of the member 9 and the packing ring in the formation, as bestshown in Figure 2 of the drawings. The part 9, acting in the manner of acaisson bell excludes drilling fluid from an area of the bottom end wallof the well thereby sealing 01? said area. With the barrel A thus heldagainst downward movement, upon further lowering the drill string,member B will move downwardly within barrel A and against the resistanceof the spring 8 thereby bringing the firing pin 22 into contact with thepercussion cap or detonator 16, thus effecting explosion thereof. Theflame of the explosion will pass downwardly through the passage providedbetween the meeting edges of the breech blocks 19 and through theopening 21 in the top of the hell or chamber 9 and fire the charge 11contained therein. The effect of the explosion of the charge 11 is toburn, blast or form the cavity H in the formation as shown in Figures 2and 3. The shape and dimensions of the cavity H may be controlled byregulating the shape and dimensions of the recess 12 in the charge; thekind and amount of high explosive in said charge, and the distancebetween the base of the recess 12 in the charge and the surface of thebottom end wall of the bore of the well.

It will, of course, be understood that as the result of the explosion ofthe charge 11, the interior of the hell or chamber will be empty and thelower end of the firing pin 22 may readily pass downwardly through thechamher and through the opening in the nut or bushing 15. During thedownward movement of the member B, the valve 3 will be turned to an openposition by the gear or pinion 3 on the outer end thereof travelingdownwardly in mesh with a rack 43 rising from the nut 15. The firing pin22 will then enter the cavity and by reason of the perforations 25,fluid in the cavity will pass into the bore of the firing pin or nozzleand thence upwardly into the bottom of the trap chamber 1 under thepressure diflerential existing between the formation and the trapchamber.

When the combined firing pin and nozzle enters the cavity C, a packing44 carried by and surrounding the nozzle will seal the same therein asshown in Figure 3, whereby formation fluid under its natural pressure isprevented from escaping upwardly through the top of the cavity anddrilling fluid is prevented from leaking into the cavity.

It will here be explained that a very small quantity of drilling fluidmay be trapped Within the open bottom of the bell member 9 and below thehood 23. However, the action of the explosion of the charge 11 willdissipate such drilling fluid and therefore no drilling fluid as suchwill be within the bottom of the hell 9 and therefore there 6 is 'nopossibiliy of drilling fluid entering the top of the cavity C.

The firing pin or nozzle 22 is permitted to remain in the cavity for asufficient length of time to ensure that a desired amount of formationfluid will flow into the trap chamber under the differential between thepressure in the formation and the atmospheric pressure in the chamher.The valve 3 is then closed to trap fluid within the chamber. To closethe valve '3, the drill string is slowly raised, thus removing theweight thereof from the latch 2? and permitting the spring 8 to expand,thereby holding down the member A in position in contact with theformation and at the same time moving the member B upwardly within themember A. By virtue of the intermeshing of the pinion 3 carried by thevalve 3 and the rack 43 carried by the member A, the relativelongitudinal movement between the members A and B will rotate the gear 3and close the valve. Subsequently, by operation of the wire line, thelatch 29 may be withdrawn from engage ment with the drill collar and thetool containing the trapped sample may be elevated to the surface. TheWire line overshot 26 may then be removed and the contents of thechamber 1 drawn off by a suitable con nection engaged with the threadedsocket 45, the valve 46 being opened for this purpose.

What I claim is:

l. A retrievable device for lowering through a drill string duringdrilling operations for obtaining samples or specimens of fluid from theformation below the bottom of an oil well, comprising a pair of slidablyconnected members, one member carrying a shaped charge and a detonator,the other member having a firing pin in cooperative relation with thedetonator and having a longitudinal bore open at opposite ends, saidfiring pin being mounted on said other member for projection below thebottom of the device for receiving fluid from the formation.

2. A retriievable device for lowering through a drill string duringdrilling operations for obtaining samples or specimens of fluid fromtheformation below the bottom of an oil well, comprising apair ofmembers slidable upon one another, one member being provided with anexplosive charge chamber opening through the bottom thereof, a detonatorseat in cooperative relation with the explosive charge chamber, theother member being provided with a firing pin in cooperative relationwith the detonator seat and having a longitudinal bore open at oppositeends, a trap chamber carried by said other member and communicating withthe inner open end of the bore, said other member capable of movement onsaid first member to project its firing pin through the detonator seat,through the explosive chamber and through and beyond the open endthereof, whereby the firing pin may constitute a conduit for leadingformation fluid into the trap chamber.

3. A retrievable device for lowering through a drill string duringdrilling operations for obtainingsamples or specimens of fluid from theformation below the bottom of an oil Well, comprising a lower barrelmember, a plunger member telescoping with the barrel member, a caissonbell carried by the barrel member and constituting an explosive chargechamber, a firing pin carried by the plunger and provided with alongitudinal bore open at opposite ends, a detonator seat in cooperativerelation with the explosive charge member and with the outer end of thefiring pin, and a trap chamber carried by the plunger member andcommunicating with the bore of the firing pin.

4. A retrievable device for lowering through a drill .string duringdrilling operations for obtaining samples or specimens of fluid from theformation below'the bottom of an oil well, comprising a lower memberhaving its bottom end provided with means for engagement with the bottomof an oil well and sealing oil drilling fluid from an area of the bottomend wall of the well, an upper member slidable on the lower member,means carried by the lowermember for forming an opening through thesealed oif area of-the bottom end wall of the well and a cavity in theunderlying formation, and nozzle means carried by the upper member foractuating said opening forming means and projectable beyond the lowerend of the lower member for movement into the cavity.

5. A retrievable device for lowering through a drill string duringdrilling operations for obtaining samples or specimens of fluid from theformationrbelow the bottom of an oil well, comprising a lower barrelmember provided at its bottom end with a caisson bell having a shapedcharge member, a detonator seat provided in the barrel in cooperativerelation with the shaped charge chamber, a pair of opposite slidablebreech blocks between the detonator seat and the shaped charge chamber,the meeting edges of the breech blocks having cooperating groovesforming a passage communicating from the detonator seat to the shapedcharge chamber, and a plunger slidable within the barrel and providedwith a trap chamber, a firing pin carried by the plunger and having alongitudinal bore open at its opposite ends and in communication withthe trap chamber, the said plunger being movable upon the barrel toproject the lower end of the firing pin into and through the detonatorseat and in between the breech blocks'to separate the same anddownwardly through and beyond the open end of the barrel.

6. A device of the class described comprising an upright lower memberhaving means for supporting it upon and within a drill string, an uppermember slidable vertically on and projecting above the lower member andprovided with a chamber, and an open ended tube depending from the uppermemberand in communication with the bottom of the chamber, theprojecting portion of the upper member having an overshot latchmechanism for connection with a drill string whereby said upper membermay be lowered by lowering the drill string to project the tube belowthe lower member, and spring means bearing in opposite directionsagainst said members for elevating the upper member on the lower memberwhen the upper member is disconnected from the drill string.

7. The combination with a drill string, of an open ended barrel memberwithin the bottom portion of the drill string and having a supportingconnection there with, a plunger telescoped through the open top of thebarrel and extending upwardly therefrom, said plunger being providedwith an internal chamber and an open ended tube depending therefrom andcommunicating with the chamber, the upper part of the plunger above thebarrel being connected with the drill string whereby the plunger may belowered through the barrel by downward movement of the drill string, theplunger having an extent of movement such that the tube thereof may belowered through and beyond the open bottom of the barrel.

The combination with a drill string, of an open ended barrel memberwithin the bottom portion of the drill string and having a supportingconnection therewith, a plunger telescoped through the open top of thebarrel and extending upwardly therefrom, said plunger being providedwith an internal chamber and an open ended tube depending therefrom andcommunicating with the chamber, the upper part of the plunger above thebarrel being connected with the drill string whereby the plunger may belowered through the barrel by downward movement of the drill string, theplunger having an extent of movement such that the tube part thereof maybe lowered through and beyond the open bottom of the barrel, and springmeans between the barrel and plunger for elevating the plunger when theplunger is disconnected from the drill string. I p

- 9. The combination with a drill string, of an open ended barrel memberwithin the bottom portion of the drill string and having a supportingconnection therewith, a plunger telescoped through the open top of thebarrel and extending upwardly therefrom, said plunger being providedwith an internal chamber, an open ended tube depending therefrom and incommunication with the chamber, the upper part of the plunger above thebarrel being connected with the drill string, whereby the plunger may belowered through the barrel by downward movement of the drill string, avalve between the tube and the chamber, there being a valve operatingengagement between the valve and the barrel near the lower limit of theplunger such as will open the valve during downward movement of theplunger and close the valve during upward movement thereof, and springmeans to elevate the plunger from its lower limit and thereby closethevalve.

10. The combination with a drill string, of an open ended barrel memberwithin thebottom portion of the drill string and having a supportingconnection therewith,

a plunger telescoped through the open top of the barrel 7 and extendingupwardly therefrom, said plunger being provided with an internalchamber, an open ended tube depending from the plunger and communicatingwith the chamber, the upper part of the plunger above the barrel beingconnected with the drill string whereby the'plunger may be lowered bydownward movement of the drill string, a valve controlling communicationbetween the tube and the chamber, there being a valve operatingengagement between the valve and the barrel near the lower limit ofmovementof the plunger such as will open the valve during downwardmovement of the plunger and close the valve during upward movementthereof, such engagement being provided by a pinion on the valve, and arack on the barrel in the path of downward movement of the pinion nearthe lower limit thereof, and spring means to elevate the plunger fromits lower limit and travel the pinion along the rack and thereby closethe valve.

11. A device for obtaining samples or specimens of formation fluidcomprising in combination, a drill string, a member having a boretherethrough, said member being telescopically disposed within the drillstring, means for suspending said member from the drill string with atleast the lower end of the member projecting below the drill string forengaging the bottom end wall of the well, a shaped charge within saidmember adjacent the open lower end thereof, a detonator within saidmember above the shaped charge, formation fluid extracting meansslidably disposed within said member and normally disposed above thedetonator, latch means on said extracting means engaged with said drillstring whereby the extracting means is moved with the drill string, saiddetonator being disposed in the path of movement of said extractor meanswhereby the shaped charge is detonated upon downward movement of theextractor means and forms a pocket in the bottom end wall of awell-immediately in advance of the downwardly moving extractor means,and means on said extractor for sealing 01f said pocket.

References Cited in the file of this patent Ramsey Jan. 15, 1952 was ,4,

1. A RETRIEVABLE DEVICE FOR LOWERING THROUGH A DRILL STRING DURINGDRILLING OPERATIONS FOR OBTAINING SAMPLES OR SPECIMENS OF FLUID FROM THEFORMATION BELOW THE BOTTOM OF AN OIL WELL, COMPRISING A PAIR OF SLIDABLYCONNECTED MEMBERS, ONE MEMBER CARRYING A SHAPED CHARGE AND A DETONATOR,THE OTHER MEMBER HAVING A FIRING PIN IN COOPERATIVE RELATION WITH THEDETONATOR AND HAVING A LONGITUDINAL BORE OPEN AT OPPOSITE ENDS, SAIDFIRING PIN BEING MOUNTED ON SAID OTHER MEMBER FOR PROJECTION BELOW THE